This disclosure relates to anti-counterfeiting, anti-tampering and traceability for valuable items. Each of these three security issues is generally addressed using a specific approach.
To prevent counterfeiting, prior art approaches are often based on special markings (like holograms, DNA codes, optically variable inks, invisible inks, Cryptoglyph, microtext, etc.) where an operator checks if the marking is there or not. Such solutions are useful mainly against counterfeiting (and tampering in some cases) and their security principally relies on the complexity to counterfeit the marking. In particular, invisible markings may be printed over a surface of the valuable item or good, as described for instance in applicants patents U.S. Pat. No. 7,492,920, U.S. Pat. No. 7,684,088, and U.S. Pat. No. 7,965,862.
To prevent tampering, most prior art solutions are either based on a redundant encoding strategy or on a tamper evident approach. Redundant security is based on a double encoding of critical information (like the name on a passport which is also encoded in the attached magnetic strip, or the hash of a text which is printed on a document which should not be modified). Tamper evidence can also be achieved using various physical or chemical means, which enable to detect modifications performed to a document or to a package. Such means include special paper treatments that enable it to be immediately colored by solvents or ultrasonic detection systems, which are capable of detecting an overlay of a thin piece of paper.
Traceability is achieved using a unique identification of each item. Traceability systems typically require a central database to maintain a record of information for each numbered item. The unique identification can be added to the item for instance by printing a barcode encoding a unique number, or by using unique item properties and storing them in the database, similar to the human fingerprint. It should be noted that unique identification potentially enables addressing all security issues like counterfeiting, tampering and diversion in a joint approach.
For carton and paper items, unique identification is often performed by ink-jet printing (DOD or continuous), laser printing, or engraving of an alphanumeric identifier or an information carrying code, such as a barcode, 2D matrix code, or QR code.
In the case of tampering detection, a major goal of the anti-tampering method is to guarantee that data printed in clear text on a document has not been illegally modified (for instance to increase of the face value of a check). As an example, one simple way to reach this objective is to uniquely identify the document with an identification number printed on it (for instance using a barcode or hexadecimal string). This number gives access through a look-up table to all the data printed in clear text on the document. It is then possible to check if the data printed on the document matches with the data stored in the look-up table. Optical Character Recognition/OCR may be used for automating the comparison process. An exemplary solution for integrity check of identity documents is described in U.S. Pat. No. 6,920,437, while another for passport documents is detailed in U.S. Pat. No. 6,565,000.
Traceability is particularly important for monitoring the supply chain of valuable items and tracking parallel import of goods (diversion—gray market goods). In order to track the diversion of goods, unique identifiers for each package may be recorded in a database along with the target country and other supply chain related data. In the case of gray market, the good may re-imported (diverted) into a country different from the original target country. By retrieving the unique code identifier it is then possible to trace back the origin of the good and the original target country. Exemplary system architectures of such an approach, comprising a central server, a central database and client applications, are described for instance in U.S. Pat. No. 6,922,687 and U.S. Pat. No. 6,547,137, where the identifier is printed on a label attached to the product. For the pharmaceutical industry, this solution may also be implemented by marking the identifier directly on a label or a pill as described in U.S. Pat. No. 6,776,341. For the electronic industry, U.S. Pat. No. 6,629,061 describes a solution where the identifier is printed on the circuit board and embedded in the memory device; another approach for fighting gray market in the power supply industry is given in U.S. Pat. No. 6,459,175. For the clothing industry, U.S. Pat. No. 6,461,987 describes a solution where a unique identification is obtained by the means of micro label strips.
In the case of counterfeit detection, identifiers of all the produced packages or documents are kept in a central database. For each product it is then possible to interrogate the database and know:                If the identifier belongs to the database. If so, then it is the proof that this is a valid identifier, i.e. it has not been invented by a counterfeiter (in some cases identification numbers are randomly chosen using a secret algorithm).        If another request has already been sent for the same identifier, which may indicate that several counterfeit copies of the same product exist. This method is not very reliable since the server may be unable to differentiate between this case and several authentications of the same genuine product without additional intelligence. By default, in the case where a counterfeiter takes a genuine product and copies it many times, the first authentication attempt of a fake product will be positive as the first request on the database, while a later first authentication request of the genuine product may fail as the second request to the database.        
Some of the latter solutions for traceability also apply to counterfeit detection, for instance U.S. Pat. No. 6,776,341 using labels or U.S. Pat. No. 6,461,987 using micro label strips for the clothing industry. The application of the code can be performed either by means of printing or engraving as described for instance in U.S. Pat. No. 6,706,314, where a laser may be used for reading the code either for traceability or for anti-counterfeiting applications. Special light sources may also be used with material reacting to specific wavelengths. While this approach usually only provides a binary answer (since it is capable of generating a very limited number of different identifiers), patents U.S. Pat. No. 6,384,409 mentions fighting gray market using this approach. Biological markers may also be used, as described in U.S. Pat. No. 6,030,657, or magnetic patterns, as described in U.S. Pat. No. 5,975,581, with dedicated readers.
The unique identification methods of the prior art as described above therefore enable to solve three different security issues: anti-tampering, traceability and anti-counterfeiting. However, they have some critical drawbacks in practice:                The answer given by the central server is not reliable: products detected as authentic might actually be fakes, and vice-versa;        They require applying a unique code on each item, which is expensive.        They require a dedicated connection from the reader/detection device to a central server.        
An additional limitation of the above solutions is that they primarily rely upon the addition of a 2D information, such as a barcode, a covert marking or a printed identifier, to a valuable item or good material or printed surface. This limitation to 2D reduces the search space for potential counterfeiters who can devote significant effort and investments to extract and reproduce the security features. For certain applications, it may therefore be desirable to extend the security features to additional material dimensions.
In that context, a different approach enabling unique identification without applying a unique code, sometimes referred to as “fingerprint” or PUF (Physical Unclonable Function) may be used. The fundamental approach consists in precisely measuring/identifying/characterizing some intrinsic features of the document or product material or surface and use it in order to identify the product uniquely. Features can for instance be color fluctuation, surface roughness, material structures, etc. For instance, Ingenia Technology proposed to measure the micro topology of carton and paper with a coherent light source (typically produced by a laser) for unique identification purposes in patent applications GB0418138.4, GB0418173.1, GB0418178.0 and GB0509635.9. This technology may be directly embedded in printer device, as described in PCT/GB2005/000903. This technology can basically be used on any chaotic surface, using an array of laser sources enabling to probe the material surface at various incidences, as described in PCT/GB2005/000922. A similar approach was described in application GB2221870 from De La Rue Company Plc, where the scattering of a coherent light was used for detection. Another solution is described in U.S. Pat. No. 6,584,214 by MIT where the whole 3D chaotic structure of a material is used to generate a unique identifier. The 3D structure is acquired using devices based on coherent light (for non-transparent material) or ultrasound and X-rays (for transparent materials). Another approach using ultrasonic measurement is described in U.S. Pat. No. 5,454,045, where features (either macroscopic or microscopic) are measured inside a material, stored and subsequently compared with new measurements for matching controls.
In published patent applications US20050075984, US20030014647 and US20030712659, a method based on random set of micro bubbles inserted in a transparent medium and stuck on products is described. The detection is based on measurement of shadows and reflections from a single 2D image capture to determine a unique signature for each set of bubbles. The transparent medium is then physically affixed to the product or document to be identified. This approach is unusual as it is somewhat between two approaches: on the one hand it is an analog random process but on the other hand it requires the transparent medium to be physically applied on the product which is conceptually the same approach as printing out a serial number, yet with an extra micro bubble depth.
Another family of solutions is based on the creation of a digital signature using the random and chaotic nature of materials. Such a digital signature can be used for authentication purposes, for encryption purposes or for tampering detection. Applications related to authentication are for instance disclosed in U.S. Pat. No. 6,928,552, where the signature is encrypted and printed on the material itself as a unique image for each item sample. Various patent applications disclosed by the company Signoptic Technologies also focus on the generation and use of a digital signature using material microstructure. In document WO2005/122100, different applications are described where the signature is used to encrypt data. Document WO2006/078651 focuses specifically on signatures obtained from fibrous materials for authentication purposes. U.S. Pat. No. 8,994,956 and WO2008053121A2 describe specific optical devices and accessories for the observation, by reflection, of structural details of an object at millimeter or sub-millimeter scales.
Thus, the prior art approaches still have one or more of the following drawbacks in anti-counterfeiting practice:                Fingerprinting technologies require capture of thousands or even millions of reference images for all possible intrinsic features that may be encountered in the genuine set of items to authenticate. Moreover, each image must be of controlled quality, indeed any bad reference image will result in an unreliable answer (false positive or false negative). In a real world industrial environment where production can take place in a number of remote places, this requirement may increase the cost of deployment to an unacceptable level. Two particular examples of added costs are the hardware and software infrastructure setup or production delays (production must be stopped in case of network or imaging issues for instance).        Most authentication methods based on the material structure require a network access to a central server and computing system, which limits their use to connected areas and slows downs substantially the authentication process.        Detection and classification into genuine versus counterfeit require specific acquisition devices, such as coherent light beamers, magnifiers or special optical accessories, in order to enable the detection of the intrinsic features. For a number of authentication applications, it is desirable to use standard imaging devices like smartphone cameras for instance.        
Rather than relying upon the intrinsic features of the item material or surface as in the above fingerprinting solutions, another approach consists in embossing, that is deforming, the 3D surface of a packaging foil (for instance for cigarette packets) or package for authentication purposes. As described for instance by Boegli Gravures in EP1867470, an array of identification marks such as signs, dots or patterns may be embossed on-line with the staining and the embossing of logos, possibly in the stained and/or the logo areas. The method described in EP1867470 is however limited to weak authentication, as the embossing pattern is detectable by a simple template matching image or video camera processing technique with minimal noise level thresholding, which means a counterfeiter can easily detect the embossing pattern and reproduce it by similar imaging techniques; the whole security relies upon the challenge of embossing counterfeit packets, or as suggested in EP1867470, the combination with alternative 2D authentication methods used in automatic image processing, such as gray scale correlation and methods developed by applicants as described in U.S. Pat. No. 7,492,920, U.S. Pat. No. 7,684,088, or U.S. Pat. No. 7,965,862. These solutions however only exploit the 2D space, while it is desirable in certain applications to also take advantage of the 3D dimension associated with the embossing process.
In WO2014182963 by Digimarc, two patterns of information-conveying tiles are formed, one by printing, and the other by embossing. In general, the printing includes a tiled watermark pattern that conveys plural-bit payload data that may be suitable for authentication purposes, while the embossing includes a tiled watermark pattern that conveys spatial calibration information to facilitate the retrieval of the plural-bit payload data, in accordance with Digimarc digital watermarking technology, as known to those skilled in the art of steganography and watermarking. Thus in this solution the embossing is limited to a calibration functionality and the authentication robustness still relies upon that of the underlying 2D marking technology. As mentioned in WO2014182963, embossing may also embed the marking payload, yet the Digimarc solution requires some exhaustive search steps for detection of the marking that may not be applicable real-time in such a scenario—or if it is feasible, counterfeiters may also apply exhaustive search to reverse and reproduce the embedded marking.
There is therefore a need for novel solutions that provide some or all of the following advantages:                No network connection required        No dedicated hardware required, efficient enough to work with standard smartphones        Low production cost        Challenging to counterfeit        User friendly        